The present invention is directed to extruded smoking articles such as cigarettes and to methods for making such smoking articles. The extruded cigarettes of the present invention burn back as they are smoked, but do not involve the burning of tobacco. They heat the tobacco without burning it.
Cigarettes, cigars and pipes are popular forms of tobacco smoking articles. Many smoking products and smoking articles have been proposed through the years as improvements upon, or as alternatives to, these popular forms of tobacco smoking articles. Examples of improved smoking articles are the cigarettes and pipes described in U.S. Pat. Nos. 4,793,365, 4,771,795, 4,756,318, 4,714,082, and 4,708,151, which generally comprise a fuel element, a physically separate aerosol generating means, and a separate mouthend piece.
Tobacco substitute smoking materials have likewise been proposed as alternatives to tobacco. See, e.g., U.S. Pat. No. 4,079,742 to Rainer et al.
In U.S. Pat. No. 3,258,015, Ellis et al., proposed a smoking article which had an outer cylinder of fuel having good smoldering characteristics, preferably fine cut tobacco or reconstituted tobacco, surrounding a metal tube containing tobacco, reconstituted tobacco, or other source of nicotine and water vapor. On smoking, the burning fuel heated the nicotine source material to cause the release of nicotine vapor and potentially aerosol generating material, including water vapor. This was mixed with air which entered the open end of the tube.
In U.S. Pat. No. 3,356,094, Ellis et al. modified their original design to eliminate the protruding metal tube. This design employed a tube made out of a material which became frangible upon heating, such as certain inorganic salts or an epoxy bonded ceramic. This frangible tube was removed when the smoker eliminated ash from the end of the article. Apparently no commercial product corresponding to either of the Ellis et al patents was ever marketed.
In British Patent No. 1,185,887, particularly in FIGS. 3 and 6, Ellis-like smoking articles are described comprising a fuel rod enclosed within a tubular casing, and having an axially disposed inner tube which contains an inhalable material. The inner tube was designed to disintegrate and be eliminated with the ash during burning.
Other more recent smoking articles, such as described in Sensabaugh (U.S. Pat. No. 4,793,365) involve a substantially different concept having a physically separate aerosol generating means which is longitudinally adjacent to a fuel element. Such smoking articles do not burn back substantially as the article is smoked.
U.S. Pat. No. 4,771,795 describes an elongated, cigarette-type smoking article which utilizes a dual burn rate carbonaceous fuel element that preferentially circumscribes a physically separate axially extending aerosol generating means. A metallic tube serves as the preferred container for the aerosol generating means. Generally, the tube extends from one end of the fuel element to the other, with openings at both ends.